A cross-sealing device of this type is already known from the German Offenlegungsschrift DE 37 32 033 A1 (corresponding to U.S. Pat. No. 4,947,618). It assures that the area of the later cross-sealing seam is kept free of packaging material until after the sealing takes place. The movement of the stripping rods is thereby coupled to the movement of the cross-sealing jaws in order to avoid defective tries with such a forced guiding. Namely it must be assured that the stripping rods are already below the cross-sealing jaws when the jaws produce the sealing seam, and they must move faster along the sealing area than the plastic tube in order to move the packaging material possibly existing in the area of the later occurring sealing seam toward the earlier formed seal, namely, the actual packaging volume. The stripping rods are for this purpose tied to the cross-sealing jaws by means of pivotally supported levers and are, just like the cross-sealing jaws, guided by a cam control. The arrangement requires a significant mechanical structure and is subjected to a great wear because of the high productivity of such a cross-sealing device used in high-performance tubular bag packaging machines. As a rule, it is a one-purpose device which can be adapted only with great difficulties to different packaging parameters.
The purpose of the invention is therefore to provide a cross-sealing device of the type identified in detail above in such a manner that highly sensitive and expensive mechanical forced guideways for the stripping rods are no longer needed and the structural parts therefor are wear-resistant. The structural parts can be easily replaced without any complicated mounting operations, and a user-friendly simple adapting of the system to different packaging tasks can easily be carried out.